This laboratory is engaged in the following projects: 1. Nucleotide sequence analysis of DNA. We have determined sequences near the termini of lambda, P2, 299 and 186 DNAs for the purpose of understanding the mechanism of conversion of concatemer precursors to mature DNA. We are currently conducting a similar study on T7 DNA. 2. Mitochondrial DNA from Leishmania. We are studying the structure and replication of this very complex mitochondrial DNA. In particular we are focusing on the pattern of sequence heterogeneity of the minicircles in this DNA. We are using restriction enzyme analysis and hybridization for this purose. We are also studying replication of this DNA and we are in the process of isolating replication intermedites which will be characterized by electron microscopy and other techniques.